Retroverted passage type muffler with expansion chambers



No 1952 G. H. HEDRICK RETROVERTED PASSAGE TYPE MUFFLER WITH EXPANSION CHAMBERS Filed June 14, 1948 @N bw 0 0 o o o 0 AV 0 oo 0000000 000 OO O Q O YQ 00 0000000000 ooooooooo oooooo 000 000000 0 o :o o o o $0 0 0 o 0 0 O 0 O O OnV 000 0 0 0 0 0 oooooo 0000000 o oooooo ooooooo OOOO ooo 00000000000000 0000000000000 NVENTOR: a z JiJiedzpzick, I N BY N ATTORIVM o o o o o 0 0 0 0 0 0 0 0 0 o o o 0 0 o o l looooooom:

Patented Nov. 18, 1952 RETROVERTED PASSAGE TYPE MUFFLER WITH EXPANSION CHAMBERS Gale H. Hedrick, Chicago, Ill., assignor to Marcmont Automotive Products, Inc., Chicago, 111., a corporation of Illinois Application June 14, 1948, Serial No. 32,957

1 Claim.

This invention relates to mufilers for internal combustion engines.

The primary object of the invention is to provide a muffler of the three-pass type wherein means such as a bleeding or cushion chamber is provided to dissipate the kinetic energy and absorb the pressure at one or both ends of the muffler.

Another object of the invention is to provide a three-pass muflier which produces the desired silencing without the use of resonating or tuning chambers.

A further object of the invention is to provide a mufiier wherein the sound waves generated by the gas pulses must travel a circuitous and tortuous path and there is no short cut possible for sound waves from the inlet or return tubes of the muffler.

An additional object of the invention is to provide a three-pass muffler which will be selfcleaning.

Referring to the drawings:

Figure 1 is a longitudinal sectional view of my improved muffler;

Figure 2 is an enlarged section on the line 2-2 at the inlet side of the muffler;

Figure 3 is an enlarged section on the line 3-3 at the outlet side of the muiller; and

Figure 4 is a detail view of one of the perforate tubes showing the longitudinally extending circumferentially spaced series of perforations each facing toward an opposite diametrically unperforated portion of the tube.

The muffler comprises a closed casing III having end walls or heads II and I2. The inlet tube is indicated at I3 and is supported in the end Wall I I and the spaced partitions I4, I 5 and I6 within the casing. It will be noted that this tube is spaced from the wall of the casing II), and its perforations are preferably formed as shown in Figure 4, namely, in longitudinally extending circumferentially spaced series I1, I8 and I9 opening towards diametrically opposite unperforated portions of the tube.

The gas entering the inlet tube I3 has a portion diverted through the aforesaid perforations into the closed intermediate chamber defined by partitions I5 and I6, and another portion introduced to the transverse passageway 29 at the outlet side of the muffler. The gas entering this passageway 20 from the inlet tube I3 is further divided and a portion enters the large opening 2I in a perforated partition 22. The partition 22 defines with the end wall I2 a pressure-relieving and energy-dissipating chamber 23 and it will be noted that the portion of the gas stream which enters such chamber through opening 2| is returned to the passageway 20 through the perforations 24 in the partition 22. The gas which was discharged from the tube I3 to the passageway 20 is thus divided into two portions, both of which must enter the perforated return tube 25 which communicates with the passageway 20, all as indicated by the arrows,

In the return travel, as in the case of tube I3, a portion of the gas will pass from the perforations in the tube 25 which are similar to the perforations I'I, I8 and I9, into the intermediate closed chamber between the partitions I5 and I6 to thereby further dissipate the energy and pressure.

At the discharge end of the return tube 25, namely, at the inlet side of the muffler, there is provided a similar passageway 20, as on the outlet side, and a similar pressure relieving chamber 23, as on the outlet side. Hence, the gas discharged from the return tube 25 is divided, a part passing directly from the passageway 20 to the unperforated outlet tube 26 and another part passing through the large opening 2 I to the pressurerelieving and energy-dissipating chamber 23 and back to the passageway 20 through the perforations 24.

The return tube 25, as illustrated, is supported by the unperforated partitions I5 and I6 while the unperforated outlet tube 26, which is also spaced from the wall of the casing, as shown, is supported in the partitions I5, I6, 22 and the end wall I2.

While I have shown the cushioning or bleeding chambers provided at both the inlet and outlet sides of the mufiier, such energy and pressure dissipating means may be employed at one or the other sides only.

It will be noted that the openings 2I and 2I of the chambers 23 are arranged in alignment respectively with the inlet tube I3 and the return tube 25. This is a preferable construction. Also, it will be observed that the perforations 24 and 24 are disposed throughout the area of the wall I 4 and the wall 22. Preferably, the passageways 20 and the chambers 23 comprehend the entire area of the casing. as shown.

It will be observed that the present invention departs from the usual three-pass mufiler in the provision of the energy-dissipating and pressure-relieving chambers 23 which, being open to the transverse passageways 20 throughout mit the gases to expand therein and cooperate 3 with the perforated tubes l3 and 25 to additionally dissipate energy and reduce the pressure of the gas pulses.

By reason of this construction there is no need to provide resonating chambers or tuning chambers. Moreover, there is no short-cut for the gases from the inlet tube I3 or the return tubes 25 and 26. The construction shown and described also provides a mufiier which has a high self-cleaning efficiency.

I claim:

A muffler comprising a casing with front and rear walls, a pair of spaced transverse partitions disposed within said casing adjacent and spaced in parallel relation to each of said Walls so as to define an elongated central chamber, a chamber adjacent each end of said central chamber, and a chamber adjacent each of said front and rear walls, an inlet tube extending from the outside through said front Wall and the adjacent partitions and through the partition forming the rear end of said central chamber, said inlet tube being imperforate without said central chamber and being perforate Within said central chamber, a return tube having its opposite ends extending through the partitions of said central chamher and being perforate throughout, an imperforate outlet tube extending from the outside through said rear wall and the adjacent partitions and through the partition forming the front end of said central chamber, the partition most nearly adjacent the rear wall having a plurality of small perforations and a larger opening therein of substantially the same diameter as, and in axial alignment with, the said inlet tube, the partition most nearly adjacent the front Wall having a plurality of small perforations and a larger opening therein of substantially the same diameter as, and in axial alignment with, the said return tube.

GALE H. HEDRICK.

REFERENCES CITED lhe following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,182,405 Noblitt Dec. 5, 1939 2,199,164 Robbins April 30, 1940 2,326,613 Bourne Aug. 10, 1943 2,337,299 Noblitt Dec. 21, 1943 2,337,300 Noblitt Dec. "21, 1943 

